1. Field of the Invention
The present invention relates generally to the field of electrical connectors and interface adapters for electronic devices, and in particular to interchangeable adapter modules that can be used to provide an electrical interface for a circuit board, tape cartridge system, or other add-on devices in any of a variety of different computer systems.
2. Statement of the Problem
In the computer industry, a substantial "add-on" market has developed for devices and circuit boards manufactured by third parties that can added to existing computer systems. For example, a number of manufacturers produce memory boards, disk drives, and tape backup systems that can be added to personal computers. Virtually all computer systems make provision, to some degree, for these add-on devices. Most personal computers have a number of expansion slots for this purpose, each of which have appropriate electrical connectors to interface the expansion board with the system bus and power supply. In addition, most personal computers provide a number of slots or openings in the front of the unit to house floppy disk drives, hard disk drives, or other mass storage devices such as a tape cartridge system. Each of these slots is also provided with appropriate electrical connectors to interface with the system bus and power supply. In order to function properly as part of a given computer system, an add-on device must be both physically and electrically compatible with the electrical connectors provided by the host computer system.
A problem arises due to the fact that the types of physical connectors and electrical interfaces used by various computer manufacturers for these add-on devices are different. Some computer systems use a different number of signal lines to communicate, while others use different types of connectors. For example, interfaces used in IBM personal computers are different from those used in Apple or Commodore computers. The numerous companies producing clones of IBM personal computers generally use the same interfaces as IBM to ensure complete compatibility. However, even within the IBM family of personal computers, different interfaces are used for different models. The interfaces for an IBM PS/2 computer are different from those for an IBM PC-AT, which in turn are different from those for an IBM PC or PC-XT.
Heretofore, the usual solution to this problem has been for manufacturers of add-on devices to produce a separate product customized for each type of computer system. In particular, the main circuit board of the add-on device is changed to accommodate whatever differences exist in the interface. This approach has the disadvantage of requiring a separate inventory of products and spare parts for each type of computer system, thereby resulting in higher costs for manufacturing and distributing the products. In addition, the resulting smaller volume of each product greatly reduces or eliminates any economies of scale that might otherwise be available in the manufacturing process.
3. Solution to the Problem
The present invention overcomes this problem by using a small inexpensive adapter circuit board to provide an interface for the larger, more expensive, main circuit board of the device. Given a number of these interchangeable adapters, it becomes possible to easily install the same device (including the same main circuit board) in any of a variety of different computer interface configurations.